How did mammals evolve from reptiles
Ancestor of the whale
By observing and comparing fossil remains, the paleontologist finds evidence of the characteristics and evolution of life through time. The study of fossils is essentially morphological-comparative, which allows for interpretations in the fields of functional anatomy, systematics, evolution, paleoecology, paleobiogeography, taphonomy, biostratigraphy, etc. Paleontology allows us to understand the current biodiversity and distribution of living beings on Earth and offers tools for the analysis of how climatic and geological phenomena could affect our planet in the future.
What is a fossil? A fossil is any remains or evidence of an extinct organism. In the case of vertebrates, the most common remains are usually teeth and fossilized bones; but footprints (ichnites), eggs (oolites), excrement (coprolites) and, in exceptional cases, soft tissues such as remains of skin, hair, feathers or cartilage have also been preserved.
The DPV is located in the basement of the main building of the Museum and has areas for: (a) research and specialized library, (b) preparation and conservation of fossils, and (c) the scientific collection of vertebrate fossils.
How was the change from reptiles to mammals?
Sauropsids gave rise to modern reptiles, birds and dinosaurs (Figure 1). In this way, the synapsid lineage continued to evolve, until approximately 205 million years ago, when the first mammals appeared.
How did mammals evolve?
The evolution of early mammals occurred in different directions. Of the great variety of groups there are currently only three in force: monotremes (egg-laying mammals), marsupials (mammals that have a pouch) and placental mammals (subclass Eutheria).
Why whales evolved
For example, colubrid snakes diversified when Old World ancestors colonized North and South America. These results demonstrate that mass extinctions and new biogeographic opportunities can spur evolutionary change, the authors say. "Much of the astonishing ecological diversity of snakes appears to be the result of evolutionary bursts triggered by ecological opportunities," Michael Grundler of the University of California, who co-authored the study with Daniel Rabosky of the University of Michigan, both in the United States, notes in a statement. "We found a major burst of dietary diversification in snakes after the extinction of the dinosaurs, and we also found that, when snakes arrive in new places, they often experience similar bursts of dietary diversification," he concludes.(With information from Europa Press)
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Infobae
Reptiles gave rise to birds and mammals. In primitive birds, insulating feathers conserved body heat. Consequently, these animals could adapt to cold climates. Later, some of these birds developed larger feathers on their limbs which allowed them to move up trees or helped them to jump to reach an insect. From this point on, birds were able to evolve to flight.
The abundant hair on the primitive limbs also allowed them to withstand low temperatures. Unlike birds, which retained the reptilian habit of laying eggs, mammals were able to gestate inside the mother and she was able to feed her young with secretions from her mammary (milk-producing) glands.
Being able to keep the heat in their bodies led to the development of hair in mammals, also the first mammals were characterized by laying eggs as well as reptiles, when they had their young they fed on breast milk secreted by their mothers through glands in the skin of the mother.
Whales 50 million years ago
"As this is the first four-legged whale skeleton found in South America and the entire Pacific Ocean, the discovery itself was a great surprise," study co-author Olivier Lambert wrote in an email. Lambert works at the Royal Belgian Institute of Natural Sciences.
This is the oldest known whale in this part of the world, and is the most complete skeleton ever found outside of India and Pakistan. This particular creature would have been up to 4 meters long, including the tail.
"Four-legged whales, the ancestors of today's whales and dolphins, have been found in three main regions: the geologically oldest come from India/Pakistan, somewhat younger taxa [the plural of taxonomy] have been found in North and West Africa, and even younger ones from the eastern side of North America," Lambert said.
The ancient whales also had long toes that were probably webbed, meaning they moved around a lot like today's otters. That's probably how they crossed the Atlantic Ocean, the researchers said. Today, a giant otter-like creature would have to swim a long way to migrate, but at that time in Earth's history, the distance between Africa and South America was twice as short and the currents were strong.